Colloidal-chemistry based synthesis of quantized CuInS2/Se2 nanoparticles

Ternary chalcogenide nanoparticles, CuInS2 and CuInSe2, were synthesized in high- temperature boiling organic non-polar solvent. The X-ray diffraction analysis revealed that both materials have tetragonal (chalcopyrite) crystal structure. Morphology of the obtained materials was revealed by using transmission electron microscopy. Agglomerated spherical CuInS2 nanoparticles with broad size distribution in the range from 2 to 20 nm were obtained. In the case of CuInSe2, isolated particles with spherical or prismatic shape in the size range from 10 to 25 nm were obtained, as well as agglomerates consisting of much smaller particles with diameter of about 2-5 nm. The particles with the smallest diameters of both materials exhibit quantum size effect

Elektrohemijska oksidacija 2,4,6-trihlorfenola na nano-cirkonijum - oksidnoj matrici dopiranoj gvožđem

Solvothermaly synthesized zirconium oxide nanopowders, pure and doped with various amounts of iron ions (1–20 %), were used as modifiers of glassy carbon electrodes. The modified electrodes were tested in the reaction of electrochemical oxidation of 2,4,6-trichlorophenol (TCP) in order to inves tigate the influence of doping on electrochemical performance of zirconia mat rix. The techniques of cyclic voltammetry and electrochemical impedance spectroscopy were employed. Cyclic voltammetry showed that electrooxid ation of TCP proceeded through the oxidation of hydroxyl group. Possible pathway included the formation of quinones and the formation of polyphenol film on the electrode surface, leading to the electrode fouling. Iron doping enhanced the activity of zirconia matrix towards TCP electrooxidation. Elec trochemical impedance spectroscopy showed the importance of iron content in zirconia matrix for the preferable pathway of TCP electrooxidation. The quin one formation pathway was favoured by low iron doped zirconia (doped with 1% of iron), while polyphenol film formation on the electrode surface was more pronounced at samples with higher iron ion content (for doping with 10 and 20 % of iron). The sample with 5 % of added iron ions, showed intermedНанопрахови цирконијум-оксида, чисти и допирани различитим количинама јона гвожђа синтетисани су солвотермалном методом. Добијени прахови су коришћени као модификатори електродa од стакластог угљеника. Модификоване електроде су тести- ране у реакцији електрохемијске оксидације 2,4,6-трихлорфенола (TCP), како би се испитао утицај допанта на перформансе цирконијум-оксидне матрице. За испитивање су коришћене технике цикличне волтаметрије и електрохемијске импедансне спектро- скопије. Резултати цикличне волтаметрије су показали да се електрооксидација TCP одиграва преко оксидације хидроксилне групе. Могуће даље реакционе путање су укљу- чивале формирање хинона и настајање полифенолног филма на површини електроде који доводи до пасивације електроде. Допирање јонима гвожђа је повећало активност цирконијум-оксидне матрице за електрооксидацију TCP. Резултати електрохемијске импедансне спектроскопије су указали на утицај количине јона гвожђа у цирконијум- -оксидној матрици на реакциони механизам TCP електроосидације. Реакциона путања која укључује формирање хинона је фаворизована на цирконијум-оксидним електро- дама са ниским садржајем јона гвожђа (допираног са 1 % јона гвожђа), док је форми- рање полифенолног филма дошло до изражаја на узорцима са већим садржајем јона гвожђа (допираних са 10 и 20 % јона гвожђа). Узорак цирконијум-оксида, допиран са 5 % јона гвожђа, има прелазна својства, јер долази до формирања полифенолног филма на површини електроде, али и до његове разградње

Supplementary data for the article: Savić, T. D.; Ćomor, M. I.; Abazović, N. D.; Šaponjić, Z. V.; Marinović-Cincović, M. T.; Veljković, D. Ž.; Zarić, S. D.; Janković, I. A. Anatase Nanoparticles Surface Modified with Fused Ring Salicylate-Type Ligands (1-Hydroxy-2-Naphthoic Acids): A Combined DFT and Experimental Study. Journal of Alloys and Compounds 2015, 630, 226–235. https://doi.org/10.1016/j.jallcom.2015.01.041

Supplementary material for: [https://doi.org/10.1016/j.jallcom.2015.01.041]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1661

Supplementary data for article: Savić, T. D.; Šaponjić, Z. V.; Čomor, M. I.; Nedeljkovic, J. M.; Dramicanin, M. D.; Nikolić, M. G.; Veljković, D. Ž.; Zarić, S.; Janković, I. A. Surface Modification of Anatase Nanoparticles with Fused Ring Salicylate-Type Ligands (3-Hydroxy-2-Naphthoic Acids): A Combined DFT and Experimental Study of Optical Properties. Nanoscale 2013, 5 (16), 7601–7612. https://doi.org/10.1039/c3nr01277h

Supplementary material for: [https://doi.org/10.1039/c3nr01277h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1590

Supplementary data for the article: Savić, T. D.; Ćomor, M. I.; Abazović, N. D.; Šaponjić, Z. V.; Marinović-Cincović, M. T.; Veljković, D. Ž.; Zarić, S. D.; Janković, I. A. Anatase Nanoparticles Surface Modified with Fused Ring Salicylate-Type Ligands (1-Hydroxy-2-Naphthoic Acids): A Combined DFT and Experimental Study. Journal of Alloys and Compounds 2015, 630, 226–235. https://doi.org/10.1016/j.jallcom.2015.01.041

Supplementary material for: [https://doi.org/10.1016/j.jallcom.2015.01.041]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1661

Supplementary data for article: Savić, T. D.; Šaponjić, Z. V.; Čomor, M. I.; Nedeljkovic, J. M.; Dramicanin, M. D.; Nikolić, M. G.; Veljković, D. Ž.; Zarić, S.; Janković, I. A. Surface Modification of Anatase Nanoparticles with Fused Ring Salicylate-Type Ligands (3-Hydroxy-2-Naphthoic Acids): A Combined DFT and Experimental Study of Optical Properties. Nanoscale 2013, 5 (16), 7601–7612. https://doi.org/10.1039/c3nr01277h

Supplementary material for: [https://doi.org/10.1039/c3nr01277h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1590

Synthesis and Characterization of Rutile TiO2Nanopowders Doped with Iron Ions

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5–7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO2into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence

Surface modification of anatase nanoparticles with fused ring catecholate type ligands: a combined DFT and experimental study of optical properties

Surface modification of nanocrystalline TiO2 particles (45 angstrom) with catecholate-type ligands consisting of an extended aromatic ring system, i.e., 2,3-dihydroxynaphthalene and anthrarobin, was found to alter the optical properties of the nanoparticles in a similar way to modification with catechol. The formation of inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and the reduction of the band gap upon the increase of the electron delocalization on the inclusion of additional rings. The binding structures were investigated by FTIR spectroscopy. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of catecholate type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. From the Benesi-Hildebrand plot, stability constants in methanol/water = 90/10 solutions at pH 2 of the order 10(3) M-1 have been determined. Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data

Anatase nanoparticles surface modified with fused ring salicylate-type ligands (1-hydroxy-2-naphthoic acids): A combined DFT and experimental study

Sensitization of TiO2 crystals and nanoparticles with appropriately chosen organic molecules can lead to a significant shift of their absorption threshold from the UV to the visible, thus improving the absorption of the solar spectrum as well as the efficiency of photocatalytic and photovoltaic devices. Herein, the surface modification of nanocrystalline TiO2 particles (45 angstrom) with salicylate-type ligands consisting of an extended aromatic ring system, specifically 1-hydroxy-2-naphthoic acid and 1,4-dihydroxy-2-naphthoic acid, was found to alter the optical properties of nanoparticles in a similar way to salicylic acid. From both absorption measurements and steady-state quenching measurements of modifier fluorescence upon binding to TiO2 in methanol/ water = 90/10 solutions, stability constants in the order of 10(3) M-1 have been determined at pH 2. Fluorescence lifetime measurements, in the presence and absence of colloidal TiO2 nanoparticles, indicated that the fluorescence quenching process is primarily static quenching, thus proving the formation of a nonfluorescent charge-transfer (CT) complex. The binding structures were investigated by using FTIR spectroscopy. Thermal stability of CT-complexes was investigated by using TPD analysis (TG/DTA/MS). Quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain the vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data. The investigated ligands have the optimal geometry for binding to surface Ti atoms, resulting in ring coordination complexes of a salicylate type (binuclear bidentate binding-bridging) thus restoring the six-coordinated octahedral geometry of surface Ti atoms. The formation of the inner-sphere CT-complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and a reduction in the band gap upon the increase in the electron delocalization when including an additional ring.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3337